Magnetic Field Sensing Based on Magnetoelectric Coupling of Ampere Force Effect With Piezoelectric Effect in Silver/Poly(Vinylidine Fluoride)/Silver Laminated Composite

Abstract

With the advantages of large piezoelectric constant, wide frequency response range and good flexibility, Poly(vinylidine fluoride) (PVDF) is receiving heightened attention as a promising alternative to traditional piezoelectric materials. This paper focuses on investigating the magnetoelectric effect of a three-layer composite consisting of a core layer of PVDF and two layers of silver-plated electrodes under the action of AC and DC magnetic fields. The resonance frequency of the measurement system is firstly determined to obtain the maximum magnetoelectric response. Then, the existence of magnetoelectric effect in the laminated sample is further verified, which is realized through the coupling of the piezoelectric effect and the Ampere forces caused by the eddy current under the DC bias magnetic field. The experimental results show that the magnetoelectric voltage has an excellent linear response to both AC and DC magnetic fields. The magnetoelectric voltage coefficient is obtained as 299.97 mV/cm•Oe at the resonance frequency under the DC magnetic field of 1000 Oe amplitude. Besides, the theoretical model of the magnetoelectric energy conversion is established, which matches well with the experimental results. Consequently, both AC and DC magnetic field sensing can be realized by observing the magnetoelectric voltage. Without requiring a magnetostrictive phase and power supply, the three-layer composite with a considerable magnetoelectric effect is promising for the application of online monitoring sensors used in the smart grid.

AC/DC Magnetic Field Sensing Utilizing Mechanically Mediated Product Effect of Ampere Force Caused by Eddy Currents and Piezoelectricity in a Magnetoelectric Disk

“…Because the tested sample is designed as a disk, we can approximate the eddy current loop as a concentric circle with a circumference of l = 2πr . Thus, the volume current density J(r) at a distance r from the center O is given as follows [ 24 ] where γ is the conductivity of silver. To further explore the ME coupling, a cylindrical coordinate system ( r , θ , 3) was chosen to express the ampere force and corresponding stress applied to the laminated sample under the AC and DC magnetic fields ( Figure ).…”

“…[ 23 ] In a previous work, our group presented that quite an obvious ME effect could be obtained in a rectangular polymer‐based composite. [ 24 ] Due to the advantages of a large piezoelectric voltage constant, low elastic modulus, and small dielectric constant, the polymer PVDF was expected to further enhance the ME effect. [ 2,25–28 ] The ME voltage coefficient was finally calculated as 299.97 mV cm −1 Oe −1 in resonant mode.…”

“…Due to the shape optimization of the composite, the influence of the edge eddy current on the ME conversion is overcome. Compared with the rectangular unimorph bender we reported before, [ 24 ] the force pattern of the disk has changed significantly and the ampere force and corresponding stress expressions can be derived and calculated more accurately in the radial direction. Furthermore, the ME voltage coefficient in the proposed disk is also obviously enhanced, while the AC and DC magnetic fields act vertically on the disk.…”